Dripping sounds from bathroom

Anytime my kids take a shower we hear a dripping sound downstairs but don't see a leake anywhere. What would cause this? Could water be getting between the tiles? The only area we have seen damp is behind our stove but we thought it might be the refrigerator's ice maker causing this or perhaps the water heater which is at the back of the wall the range is on. What could cause the dampness and water spots behind there? Is it possible that the drip from the bathroom upstairs could have caused this?

Most likely it is the plumbing expanding and contracting when the tub / shower is used. It is up against a stud somewher in the wall or floor and when it moves it rubs on the stud making the dripping sound.

it might be easy to tell the difference between the noises metal and water make, now that you know there are two hypotheses. Listen harder

The noise is either in the walls, on in the ceiilng. Can you locate the noise?

If you put a plastic bag into the shower drain pipe, and block the drain pipe on top too, say with another plastic bag, you'll get a pretty good seal that will hold most of the water, for hours. Fill the shower pan and see if you start hearing drip noises downstairs. If so, then it is likely that the pan leaks, under the tiles.